Active motion compensation control with a prescribable settling time of shipborne helicopter landing platforms

Shipborne helicopters have widespread applications in both civilian and military fields. The wind, waves, and currents-induced ship motions inevitably affect and even menace the safety of the deck landing of shipborne helicopters. As a ship motion active compensation device, shipborne helicopter landing platforms provide a good solution scheme for the safe landing of shipborne helicopters. This article aims to achieve the active motion compensation control with a prescribable settling time of shipborne helicopter landing platforms. To this end, we create a new barrier control Lyapunov function and whereby develop an active motion compensation control law with a prescribable settling time of shipborne helicopter landing platforms. As a result, the supporting surface of the shipborne helicopter landing platform is maintained at the desired constant position and orientations with the tolerance steady-state control error within the prescribed settling time, and hence guarantees the safe landing of shipborne helicopters. As such, it is allowed for the ship motions compensation system of shipborne helicopter landing platform to start only when the helicopter enters the obstacle free area above the deck, instead of operating all the time or starting sufficient long in advance. This way to compensate ship motions has less conservativeness and higher efficiency and is more energy-saving. Simulation results on a test platform indicate that the developed control law can make the platform compensate the ship motions accurately within the prescribed settling time.